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Particle Damping in Vibrating Cantilever Beams

Test Equipment Data Package

Completed February 17, 2004

Principal Investigator: William D. Tandy, Jr.

The University of Texas at Austin

Email: [email protected]

Phone: (512) 203-7930

Address: 2101 Burton Dr Apt 1055 Austin, TX 78741-4103-55

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Change Page

Rev. Date Process Owner Alternates

Description

Basic February 2004 William D. Tandy Timothy C. Allison Robert Ross John Hatlelid

Initial Release

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KC-135 Quick Reference Data Sheet

Principal Investigator: William D. Tandy, Jr.

Contact Information: [email protected], (512) 203-7930

Experiment Title: Particle Damping in Vibrating Cantilever Beams

Flight Date(s): April 1-10, 2004

Overall Assembly Weight (lbs.): 280

Assembly Dimensions (L x W x H): 4 X 2 X 4 ft

Equipment Orientation Requests: Cabinet against fuselage wall, facing inward

Proposed Floor Mounting Strategy (Bolts/Studs or Straps): Bolts/Studs

Gas Cylinder Requests (Type and Quantity): N/A

Overboard Vent Requests (Yes or No): No

Power Requirement (Voltage and Current Required): 110 VAC

Free Float Experiment (Yes or No): No

Flyer Names for Each Proposed Flight Day: April 7/9 - Tim Allison and Bill Tandy

April 8/10 - Rob Ross and John Hatlelid

Camera Pole and/or Video Support: 1 pole with universal camera mount.

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Table of Contents

1. Flight Manifest................................................................................................................ 1 2. Experiment Background ................................................................................................. 1 3. Experiment Description .................................................................................................. 1 4. Equipment Description ................................................................................................... 2

4.1 Equipment ................................................................................................................. 2 4.2 Proposed Layout ....................................................................................................... 5

5. Structural Analysis.......................................................................................................... 6 5.1 Test Assembly Loading ............................................................................................ 6 5.2 Floor Load Analysis................................................................................................ 10 5.3 Component Attachments......................................................................................... 11

6. Electrical Analysis ........................................................................................................ 12 6.1 Schematic................................................................................................................ 12 6.2 Load Tables............................................................................................................. 13 6.3 Electrical Kill Switch.............................................................................................. 13 6.4 Loss of Electrical Power ......................................................................................... 13

7. Pressure/Vacuum System Documentation.................................................................... 14 8. Laser Certification ........................................................................................................ 14 9. Parabola Details and Crew Assistance......................................................................... 14 10. Free-Float Requirements............................................................................................. 14 11. Institutional Review Board (IRB)............................................................................... 15 12. Hazard Analysis .......................................................................................................... 15

12.1 Hazard Sources ..................................................................................................... 15 12.2 Detailed Hazard Description................................................................................. 16

13. Tool Requirements...................................................................................................... 20 14. Photo Requirements .................................................................................................... 20 15. Aircraft Loading.......................................................................................................... 20 16. Ground Support Requirements ................................................................................... 21 17. Hazardous Material..................................................................................................... 21 18. Material Safety Data Sheets (MSDS) ......................................................................... 21 19. Procedures................................................................................................................... 21

19.1 Equipment Shipment to Ellington Field ............................................................... 21 19.2 Ground Operations................................................................................................ 22 19.3 Loading ................................................................................................................. 22 19.4 Pre-Flight .............................................................................................................. 22 19.5 Take-off/Landing .................................................................................................. 22 19.6 In-Flight ................................................................................................................ 23 19.7 Post-Flight............................................................................................................. 24 19.8 Off-loading............................................................................................................ 24

20. Bibliography ............................................................................................................... 24

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1. Flight Manifest

If possible, the team would prefer to fly on April 7-8. Table 1 describes the team

members who will be flying:

Table 1: Flight manifest table.

Name Position Preferred Flight Date

Flown on KC-135 Previously?

William Tandy Flight Crew April 7/9 No Robert Ross Flight Crew April 8/10 No John Hatlelid Flight Crew April 8/10 No Timothy Allison Flight Crew April 7/9 No Christopher Gilmore Alternate Flyer As needed No

2. Experiment Background

This experiment is being flown on the KC-135 to determine the effect of a

microgravity environment on particle damping. Particle damping offers a possible

solution to unwanted vibrations in aerospace structures, but the concept has never been

implemented because it has not been tested in a microgravity environment. If the results

of our experiment are promising, we anticipate that future experiments will also be

conducted to determine the feasibility of particle damping in aerospace structures.

3. Experiment Description

The team will research the effects of particle damping in one g and zero g

environments and compare the results. The transient and steady-state responses of 24

harmonically excited cantilever beam samples will be measured with the National

Instruments’ LabView software package. The samples will be constructed from hollow

aluminum rods and be filled to specific fill ratios with various particles. As each rod is

excited with a vibrator, data from accelerometers placed on the sample and on a reference

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point will be acquired with LabView for post-experimental analysis. Our goal is to

isolate the effects of particle mass, diameter, fill ratio, and gravity on the vibrating system.

We anticipate that the absence of a gravitational field will allow particles to collide for

greater period of time, dissipating more energy and damping out the beam vibrations

more quickly than in a one g environment.

4. Equipment Description

4.1 Equipment Figures 1 through 3 show the experimental setup and the hardware components

and parts are summarized in Table 2. The experiment will be attached to the aluminum

floor spacers in the KC-135 test cabin; it will not free float. Table 3 is a list of

components that are not pictured in Figures 1 through 3.

Table 2: Hardware components and parts

Component Name Size Location Weight 1 Bolts 8-32X 1.25 in 5’ L-clamps to base 0.1 oz 2 Bolts 8-32 X 0.5 in A-iron to A-iron 0.5 oz/10 3 Bolts 8-32 X 0.75 in 7-ply to A-iron 0.7 oz/10 4 Screw Nuts Aug-32 To all 8-32 bolts 0.3 oz/10 5 Washers #8 A-iron & L-clamps 0.2 oz 6 Washers 1 in Base 0.2 oz 7 L-Clamps 5 in Frame to Base 6.3 oz 8 L-Clamps 2.5 in Frame to Shelves 1.0 oz 9 T-hinge 4 in Frame to Doors 1.8 oz 10 Safety Hasp (locks) 2.5 in Doors 0.9 oz 11 Angle Iron 6 ft Frame 0.875 lb/ft 12 Support Iron 6 ft Frame 0.267 lb/ft 13 Caster Wheels 1.5 in Bottom of base 1 lbs 14 7-ply 4 x 8 ft Walls of base 1.1625 lb/ft^2 15 Plexiglass 4 x 4 ft Lower Door 1.43 lb/ft^2 16 MDF 4 x 8 ft Base of test bay 1.875 lb/ft^2 17 Primer Gallon Test bay 15 lbs

18 MA 35

Accelerometer 2” x .75” Test Specimens 1.4 oz

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19 SCC Line

Conditioner In test bay 3 lbs

20 NI SCC-ACC01 In SCC conditioner 1 oz 21 Laptop Top shelf 5 lbs 22 DAQ Card In laptop 2 oz 23 Function generator 2nd shelf 6 lbs 24 Shaker Base level 8.25 lbs 25 Shaker Amplifier 2nd shelf 15 lbs 26 Surge Protector Top shelf 0.5 lbs

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Digital Video Camera

Attached to universal camera

mount

0.5 lbs

28 Cantilever Beams 2 ft Attached to Shaker 0.5 lbs 29 Fill Material N/A In Beam 0.5 lbs 28 Total Weight 280 lbs

Figure 1: Frame base & walls attachment schematic.

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Figure 2: Angle iron upper corner assembly for frame.

Figure 3: Test bay schematic

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Table 3: Components not illustrated and their specific locations

Component

Name Size Location

3 Bolts 8-32 X 0.75 in Used to attach the 7-ply to the frame

6 Washers 1 in Used in the base for strength between the MDF and 5''

L-clamps 8 L-Clamps 2.5 in Used to secure shelves to frame

13 Caster Wheels 1.5 in Temporary wheels used to aid test bay movement 17 Primer Gallon Used to seal the test bay base and walls

19 SCC Line

Conditioner Will be located on the 2nd shelf with components 23 &

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20 NI SCC-ACC01

Located in the SCC Line conditioner

26 Surge Protector Will be located on the top shelf with component 21 29 Fill Material N/A Located inside the cantilever beam

4.2 Proposed Layout

Figures 5 and 6 depict the test cabin layout. Experimenter restraints are required

forward and aft of the assembly, as well as in front of the cabinet doors. Note that overall

test bay placement in the aft or forward of the aircraft is lenient.

Figure 5: Experiment layout on KC-135, cross-section.

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Figure 6: Experiment layout on KC-135, floor view.

5. Structural Analysis

5.1 Test Assembly Loading The structure was analyzed for failure points in the prescribed maximum gravity

loading environment described by NASA. I-DEAS 10 was utilized for its finite element

modeling and structural solver routines.

Figures 7 through 11 display the outcome of the analysis. The images were

enhanced by displaying the maximum stress for each solution both to verify the accuracy

of the solution and to show the areas that experience the highest loading. The highest

loading on the structure occurred at 9 g’s, in the forward direction at 1,620 PSI. The

highest allowable loading for the structure is 3,500 PSI. Table 4 lists the different gravity

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vectors and their corresponding stress levels, as well as the calculated factor of safety.

From the data collected it was thus determined that the structure would be well within the

safety limits. The final structure will also include angle irons and braces so that the final

factors of safety will increase beyond the current minimum case scenario.

Table 4: Summary of structural analysis

Gravity Factor of Safety Vector Magnitude (g's) Max Stress (PSI) (3500 PSI Allowed) Down 6 300 11 Forward 9 1620 2 Aft 3 540 6 Lateral 2 360 9 Up 2 250 14

Figure 7: Gravitational loading in the ‘Up’ direction with a 2g magnitude

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Figure 8: Gravitational loading in the ‘Aft’ direction with a 3g magnitude

Figure 9: Gravitational loading in the ‘Down’ direction with a 6g magnitude

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Figure 10: Gravitational loading in the ‘Forward’ direction with a 9g magnitude

Figure 11: Gravitational loading in the ‘Lateral’ direction with a 2g magnitude

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5.2 Floor Load Analysis The allowable floor load of the KC-135 is 200 lbs per spacer used to anchor the

test specimen. Our test specimen weighs 280 lbs and will use six spacers to anchor to the

KC-135. Therefore our test specimen is over supported by 920 lbs. Our test specimen

does not exceed the maximum floor load of the KC-135. The tensile and shear strength

of the bolts used to attach the specimen to the floor is 5000 lbs. Figure 12 is a free body

diagram of the maximum shear stress experience by the bolts. This is the case of a 9 g

forward load. The load is 2520 lbs, which is below the shear strength of even one bolt.

With six bolts, the factor of safety is 11. This shows that our test specimen will clearly

remain attached to the KC-135 in this case.

Figure 12: Shear loading of the floor support

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Figure 13 is a free body diagram of the maximum tensile load experience by the bolts.

This is the case of a 9 g top load. The load is 2520 lbs, which is below the tensile

strength of one bolt. Under this loading condition our test specimen will remain attached

to the KC-135.

Figure 13: Maximum tensile load

5.3 Component Attachments Each component inside the assembly will be attached to the shelves a minimum of

four steel bolts (and a metal bracket for the laptop). The heaviest component is the

shaker amplifier, which will weigh 135 lbs under 9 g conditions. Over four bolts, this is

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33.75 lbs/bolt. Each bolt has a cross-sectional area of 0.05 sq. inches, meaning that the

shear stress on each bolt will be 688 psi. The shear strength of the bolt steel is 18 ksi,

meaning that the factor of safety is 26. Because this is the heaviest component in the

assembly, factors of safety for all other components will be even higher than 26.

6. Electrical Analysis

6.1 Schematic Figure 14 shows a graphical schematic drawing showing the top-level electrical

design of the experiment:

Figure 14: Electrical Schematic

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6.2 Load Tables Table 5 and 6 are the power source details and load analysis respectively. They

describe the electrical power drawn from the external power supply:

Table 5: Power source details

Name: Power Cord 1 Voltage: 115 V, 60 HZ Wire Gauge: 12 Max Outlet Current: 20 amps

Table 6: Load Analysis

Accelerometer Module 1: 4 mA Accelerometer Module 2: 4 mA Laptop Power Supply: 1.5 A Function Generator/Amplifier: 5 A Shaker Drawn from Function generator Total Amps 6.508 A

6.3 Electrical Kill Switch In the interest of simplicity, we have decided to utilize the cutoff switch provided

on the surge protector as our main cutoff switch. Our test bay will be connected directly

to the aircraft’s AC power source via a six-plug surge protector, and all components of

the experiment will be connected to that surge protector. Killing the power to the

experiment will merely consist of turning off the surge protector.

6.4 Loss of Electrical Power In the event of a power loss, the experiment will simply stop working. The

experiment is self contained in the cabinet and all motion depends on the experiment

having electrical power. If electrical power is lost, the shaker will stop providing motion

to the system and the experiment will come to rest. The laptop will continue operating

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because it automatically diverts to battery power when not connected AC power. There

will be no potential hazards from the loss of electrical power.

7. Pressure/Vacuum System Documentation

This section is not applicable to our project; our experimental setup does not

involve any pressure/vacuum system.

8. Laser Certification

This section is not applicable to our project; our experimental setup does not

involve use of a laser.

9. Parabola Details and Crew Assistance

It will be necessary to fly at least forty 20-second parabolas over the two flight

days in order to test every sample. Flying more than forty parabolas would be helpful in

case errors occur in some testing runs. The typical sets of 8-10 parabolas with a 2-3

minute break between parabolas will be sufficient as long as there are enough sets to total

forty parabolas.

Because the experiment is designed to be run in a zero g environment, crew

notification of a steady zero g state is requested. No other crew assistance will be

necessary.

10. Free-Float Requirements

This section is not applicable to our project; the experiment will not free float.

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11. Institutional Review Board (IRB)

An IRB approval is not needed for this experiment.

12. Hazard Analysis

The following is a report on the hazard analysis of our materials used.

12.1 Hazard Sources Table 7 is the Hazard source checklist.

Table 7: Hazard source checklist, AOD form 71

1 Flammable/combustible material, fluid (liquid, vapor, or gas) NA Toxic/noxious/corrosive/hot/cold material, fluid (liquid, vapor, gas) NA High pressure system (static or dynamic) NA Evacuated container (implosion) NA Frangible material NA Stress corrosion susceptible material 2 Inadequate structural design (i.e., low safety factor)

NA High intensity light source (including laser) NA Ionizing/electromagnetic radiation NA Rotation device 3 Extendible/deployable/articulation experiment element (collision) 4 Stowage restraint failure

NA Stored energy device (i.e., mechanical spring under compression) NA Vacuum vent failure (i.e., loss of pressure/atmosphere) NA Heat transfer (habitable area over-temperature) 5 Over-temperature explosive rupture (including electrical battery) 6 High/Low touch temperature

NA Hardware cooling/heating loss (i.e., loss of thermal control) NA Pyrotechnic/explosive device NA Propulsion system (pressurized gas or liquid/solid propellant) NA High acoustic noise level NA Toxic off-gassing material NA Mercury/mercury compound NA Other JSC 11123, section 3.8 hazardous material NA Organic/microbiological (pathogenic) contamination source 7 Sharp corner/edge/protrusion/protuberance

8 Flammable/combustible material, fluid ignition source (i.e., short circuit; under-sized wiring/fuse/circuit/beaker)

9 High voltage (electrical shock) NA High static electrical discharge producer 10 Software error or compute fault NA Carcinogenic material 11 Other: Dust/debris

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12 Other: Electro Magnetic Field NA Other:

12.2 Detailed Hazard Description

1) Paint

• Hazard Description

Paint increases the combustibility of the test bay because paint is flammable.

• Hazard Causes

1) Electrical spark/surge ignites paint

2) Outside source ignites paint

• Hazard Controls

Extra attention will be taken to ensure that significant fire possibilities are at a

very minimum. (see section 6: Electrical Analysis)

2) Structural design


Structural failure or destruction of test bay under high loads

• Hazard Causes

1) High G-loads

2) Violent detachment of experiment hardware

3) Defective bolt attachment

• Hazard Controls

Structural analysis was performed and the test bay was not damaged by the

loading conditions specified by JSC. Support steel adds stiffness to the test bay

walls. This is to prevent hardware from fracturing the walls. Each piece of

hardware will also be tethered to the test bay. Loctite will be used to ensure the

tightness of the bolts and nuts.

3) Test bay doors


Test bay doors could open and collide with people onboard the aircraft.

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• Hazard Causes

1) Inadequate door restraint

• Hazard Controls

The doors will be secured shut with a latching mechanism.

4) Hardware restraints


The restraints holding the test equipment in place could fail.

• Hazard Causes

1) Excessive loading of the hardware restraints

• Hazard Controls

The test cabinet will contain any hardware that become detached from its original

position. There will also be separation between the test area, specimen storage

area, and computer / electrical area.

5) Computer battery


The computer will be driven by AC power. However, there is a battery in the

computer that could rupture.

• Hazard Causes

1) Inappropriate voltages and currents running the computer could cause the

battery to rupture.

• Hazard Controls

The computer will be connected to AC power using the correct AC adapter

provided by the manufacturer.

6) Hardware devices that produce heat


Overheated computer (or other electrically driven devices) can cause burns if

touched.

• Hazard Causes

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1) Computer (or other hardware) begins operating improperly and

overheating

• Hazard Controls

The experiment will have to be shut down in such an event. Each electrically

driven component will be plugged into a single surge protector. There will be an

emergency shutoff -switch incorporated into this surge protector. The computer

will have to be shut down manually.

7) Test bay edges


The corners and edges of the test bay could cause bodily injury if collided with.

• Hazard Causes

1) Inappropriate zero-g movements in the vicinity of the test bay.

• Hazard Controls

Hose insulation foam will pad the corners and edges of the test bay.

8) Electrical circuits


Fire can be caused by short circuit of the electrical system.

• Hazard Causes

1) Exposed wires crossing

2) Voltage surge for AC power supply

3) Liquids (i.e., water, vomit)

• Hazard Controls

All the wiring will be insulated and inspected for the integrity of its insulation.

The surge protector will protect against any other malfunctions by automatically

tripping its reset.

9) Electrical shock


The voltages being used can cause injury to a person being shocked by them.

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• Hazard Causes

1) Exposed electrical wires

2) Uncovered surge protector outlets

• Hazard Controls

All the wiring will be insulated and inspected for the integrity of its insulation.

Outlet covers will be used to shield unused outlets.

10) Software failure


Function generator begins driving at a heightened improper frequency.

• Hazard Causes

1) Improper software setup

2) Software malfunction

• Hazard Controls

In this situation the only option will be to hit the emergency kill switch.

11) Splinters and dust


Splinter and dust could come free from the test bay and cause breathing problems

to occupants and affect other experiments onboard.

• Hazard Causes

1) Micro-particles

• Hazard Controls

The test bay will be sanded and painted to minimize the presence of micro-

particles. The bay will be vacuumed before flight.

12) Electromagnetic field


While the experiment is being conducted the shaker will produce an

electromagnetic field that could cause problems with the experiment’s equipment.

• Hazard Causes

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1) The electromagnetic field is produce by the shaker

• Hazard Controls

The shaker will be positioned at the lowest point in the test bay. There will be a 2

ft. clearance between the first shelf and the base as well as a 3 ft. clearance between

the 2nd shelf and the base. Therefore, all the equipment that could be sensitive to the

electromagnetic field will be place at least two and a half feet above the shaker. This

will be sufficient clearance.

13. Tool Requirements

The only tools necessary are those used to attach the experimental setup to the

aircraft’s floor spacers via bolts/studs (such as ratchets or a monkey wrench) and will be

borrowed from the RGO if possible.

14. Photo Requirements

Neither a photographer nor a videographer is requested for in-flight

documentation. The S-band downlink is not necessary, either. One digital camcorder

will be used to document the experiment; only one universal camera pole will be

necessary.

15. Aircraft Loading

A forklift and lifting pallet will be sufficient for loading the experimental setup

into the airplane. The assembly weighs 280 lbs and will be mounted on 4 removable

casters for movement on the ground and in the test cabin, placing 70 pounds on each

wheel. After the equipment is moved into place, the casters will be removed and taken

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out of the airplane. The total weight of 280 lbs will be distributed over a base area of 8

square feet, exerting 35 lbs/sq. ft. on the floor.

16. Ground Support Requirements

After loading the equipment onto the plane, the casters will be removed and left

on the ground. Upon landing, the casters must be available for removal of the assembly.

Ratchets or monkey wrenches required to bolt the assembly to the test cabin floor are

requested.

17. Hazardous Material

Our experiment does not involve the use of any hazardous materials.

18. Material Safety Data Sheets (MSDS)

Our experiment does not involve the use of any chemicals or fluids; no MSDS are

required.

19. Procedures

19.1 Equipment Shipment to Ellington Field The team will be bringing the test assembly to Houston in a minivan on March 31,

and to Ellington Field on April 1, 2004. The assembly should be stored in a weatherproof

(indoor) facility and should not have heavy items placed on top of it. Because the

assembly dimensions are 4 x 2 x 4 ft., a minimum 4 x 2 ft. floor storage space is required.

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19.2 Ground Operations To operate the experimental setup on the ground, a 120-V ac electrical outlet is

required. After attaching a laptop to the bracket on top of the assembly, the team will

attach a rod to the vibrator. An electrical signal will be sent to the vibrator by turning on

the function generator, and accelerometer data will be acquired with LabView for

approximately 20 seconds. This test will ensure that all components and electrical

connections are working correctly. Prior to loading, there will be a general inspection of

the test bay which will include vacuuming the cabinet.

19.3 Loading The assembly will be loaded into the KC-135 test cabin with a forklift and lifting

pallet. Four casters will be inserted into holes on the bottom of the assembly base, and

the assembly will be wheeled into place along one wall of the test cabin. The casters will

be removed and the assembly base will be bolted to the aluminum floor spacers on the

KC-135. The team requests crew assistance to ensure that the assembly is securely

bolted down in the test cabin.

19.4 Pre-Flight Just prior to flight, we will conduct another general pre-flight inspection of the

test bay’s security to the KC-135, and we will insure that all components are still in their

correct operation modes. A 120-V ac outlet is required to power the experiment. While

still on the ground, LabView will be configured so that only one button will need to be

pushed during the tests in order to begin data acquisition.

19.5 Take-off/Landing During take-off and landing, the crew will situate themselves in a safe place

inside the test cabin. Because the computer will have already been prepared to begin

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testing, we request that power be provided throughout take-off. There are no special

equipment stowage requirements.

19.6 In-Flight The flight team will alternate between running an experiment and then preparing

for the next experiment on consecutive parabolas. Following are three checklists, two for

the experimental procedures and one for emergency procedures:

Checklist for Running Experiment

• Prior to parabola, move into position in front of experimental assembly • Upon notification of steady-state zero g status, depress “start” key on

computer • After 20 seconds, depress “finish” key on computer

Checklist for Preparing for Next Experiment

• Prior to parabola, move into position in front of experimental assembly • Unlatch plexiglass door • Remove safety pins from specimens • Remove point mass from specimen • Remove specimen from base mass • Unlatch Upper Bay doors • Select next specimen from storage bay • Note new specimen selected • Replace previous specimen in storage bay • Close and latch upper bay doors • Insert new specimen into base mass • Attach point mass • Insert safety pins • Close and latch Plexiglas bay door • Configure LabView for next parabola

Checklist for Emergency Procedures

• Hit the electrical kill switch • Inform pilot of the nature of the emergency • Attempt to safely resolve the situation (depends on what emergency

occurs) • Follow any emergency instructions provided by the RGO.

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19.7 Post-Flight Upon completing a flight, all experimental data will be backed up onto a second

laptop computer. A post-flight inspection will be conducted to ensure that all rods are

stored correctly for beginning the next day’s flight.

19.8 Off-loading After the assembly has been unbolted from the test cabin floor, casters will be

inserted into the base and the assembly will be wheeled onto a lifting pallet and off-

loaded by a forklift. The team will remove the equipment from NASA property via

minivan on their way home.

20. Bibliography

This section does not apply to this document; no external works were referred to.

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